Posthole digger



Feb. 1, 1955 H, A, PROMO. 2,701,124

POSTHOLE DIGGER Filed March 11, 1952 INVENT OR 19. ,4. Peon/x0 ATTORNEY United States Patent POSTHOLE DIGGER Harry A. Pronio, Zanesville, Ohio Application March 11, 1952, Serial No. 275,920

3 Claims. (Cl. 255--19) The present invention relates to earth boring apparatus and more particularly to a post hole digger which is adapted to be mounted on a tractor and operated through the power take-off of the tractor.

In the patent to Daryl W. Porter et al., No. 2,493,261, patented January 3, 1950, there is disclosed an earth boring apparatus over which the present apparatus constitutes an improvement. The improvement resides in the specific structure of the numerous novel features contributing to an improved post hole digger.

An important object of the present invention is the provision of a novel bearing and mounting arrangement for the auger which prevents damage to the auger and which permits ready replacement of worn parts.

A further feature of the present invention resides in the specific manner of mounting the various parts of the boring unit to make the auger completely rigid.

Additional objects and features of the present invention will be apparent from the following detailed description of a preferred embodiment of the invention taken in connection with the accompanying drawing wherein:

The single figure discloses an elevational view partly in section of the improved boring unit forming the subject matter of the present invention.

Referring to the drawing, numeral designates the shaft which is connected to the power take-off of any conventional tractor (not shown). The shaft 10 is connected to the shaft 11 through a suitable universal joint 12. The shaft 11 is connected to the joint 12 by means of a shear pin 13 which will break and render the universal joint inoperative if rock or other obstructions are encountered beneath the surface where the digging operation is taking place.

The casing, indicated by numeral 14, encloses the cooperating bevel gears 15 and 16. The gear 15 is connected to the shaft 11, which is suitably supported in the casing by bearings 17 and 18. The gear 16 is rigidly supported in the bearing 19 carried by the removable cover plate 20 forming an upper housing. The vertical axle 21 is keyed to gear 16 as indicated by numeral 22 and is supported in its rotation by bearing 23 carried by the lower housing 24.

The housing 24 is substantially hollow except at its lower end 25 through which the axle 21 extends. The housing 24, as well as the casing 14 and upper housing above gear 16 is filled with grease or oil to insure adequate lubrication. As seen in the drawing, the housing 24 tapers downwardly and is surrounded by the auger 26.

The auger 26 is in the form of a tube 27 to which the auger blade 28 is welded. The tube has a reduced lower portion 29 which contacts the axle 21 and is keyed thereto at 30. Within the lower end of the tube 27 and surrounding the lower end of housing 24, roller bearings 31 are provided. The lower end of the casing is provided with a shoulder 32 for retaining the roller hearings in place. A pillow bearing support 33 is secured to the 2,701,124 Patented Feb. 1, 1955 ice lower housing 24 and receives the upper end of the tube 27. Suitable openings 34 are provided in the pillow bearing support to receive a suitable lubricant such as grease.

The lower end of the axle 21 carries a coal mine auger 35 removably secured to the axle in any conventional manner.

It will be readily apparent from the foregoing description that the structure shown is well adapted to accomplish the objects of the invention. To disassemble the boring unit, the auger 35 is first removed thereby enabling ready removal of the auger tube 26, to permit access to the interior of the lower housing. The lower housing 24 and upper housing 20 are bolted to the casing 14 and removal of these housings enable ready entry to the parts within the casing. When the auger blade 26 becomes worn, the entire auger tube is replaceable. The bearings 19 and 23 results in a double bearing for rigidly supporting the axle 21.

Thus, it will be seen that the construction described results in a rigid earth boring tool of relative simplicity. It will be understood that minor changes may be made in the embodiment shown within departing from the spirit of the invention.

. Having thus described the invention, what is claimed 1. An earth boring tool comprising a casing, a pair of cooperating bevel gears within the casing, a housing depending from said casing, a shaft connected to one of said gears and adapted to be connected to a power take-off, an axle connected to said other gear and extending through said housing, an auger tube surrounding said housing, means for detachably securing said auger tube to the lower end of the axle, bearing means positioned between the auger tube and the housing, and an additional auger detachably secured to the lower end of the axle.

2. An earth boring tool comprising a casing, a pair of cooperating bevel gears within the casing, a shaft connected to one of said gears and adapted to be connected to a power take-off, a housing depending from said casing, a bearing supported in the upper portion of said housing, an axle connected to said other gear and extending through said bearing and said housing, an auger tube surrounding said housing, means for securing said auger tube adjacent the lower end of the axle, bearing means between the auger tube and the housing, and an additional auger detachably secured to the lower end of the axle.

3. An earth boring tool comprising a casing, a pair of cooperating bevel gears within the casing, a shaft connected to one of said gears and adapted to be connected to a power take-off, a housing depending from said casing, a bearing supported in the upper portion of said housing, an axle connected to said other bevel gear and extending through said bearing and said housing, an auger tube surrounding said housing, means for securing said auger tube adjacent the lower end of the axle, bearing means between the auger tube and the housing adjacent the lower end of the housing, an additional auger detachably secured to the lower end of the axle, and a pillow bearing support mounted on said housing adjacent the upper portion thereof for receiving the upper end of the auger tube.

References Cited in the file of this patent UNITED STATES PATENTS 

